Expandable metal fishing tool

ABSTRACT

Disclosed herein are aspects of an expandable metal fishing tool for use in a wellbore. The expandable metal fishing tool, in one aspect, includes a mandrel. The expandable metal fishing tool, according to this aspect, further includes one or more expandable members positioned at least partially along an interior surface or an exterior surface of the mandrel, wherein the one or more expandable members comprise a metal configured to expand in response to hydrolysis, and further wherein a combined volume of the one or more expandable members is sufficient to expand radially to engage a downhole tubular within a wellbore in response to the hydrolysis.

BACKGROUND

It is common for objects, such as a segment of production tubing, to become severed (e.g., intentionally or for repair) within a wellbore. Tools for retrieving the severed objects, or reattaching to the severed objects, are well known. These tools are known in the art as fishing tools.

One type of fishing tool is known as an overshot tool, because the overshot tool engages the object disposed within the wellbore, by encircling it. While overshot tools are widely used; most of these known overshot tools cannot retrieve and/or attach to a wide range of different sized objects, and/or lack the necessary anchoring capacity or sealing capacity.

What is needed in the art is an improved fishing tool that does not have the limitations of existing fishing tools.

BRIEF DESCRIPTION

Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a well system including an exemplary operating environment that the apparatuses, systems and methods disclosed herein may be employed;

FIGS. 2 and 3 illustrate various different configurations for an expandable metal fishing tool designed and manufactured according to the disclosure;

FIGS. 4-9 illustrate various different configurations for an expandable member (e.g., for use in an expandable metal fishing tool) designed and manufactured according to the disclosure;

FIG. 10 illustrates an alternative configuration for an expandable metal fishing tool designed and manufactured according to the disclosure; and

FIGS. 11A-11C different cross-sectional views of a well system including an expandable metal fishing tool at various different stages of use.

DETAILED DESCRIPTION

In the drawings and descriptions that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals, respectively. The drawn figures are not necessarily, but may be, to scale. Certain features of the disclosure may be shown exaggerated in scale or in somewhat schematic form and some details of certain elements may not be shown in the interest of clarity and conciseness.

The present disclosure may be implemented in embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed herein may be employed separately or in any suitable combination to produce desired results. Moreover, all statements herein reciting principles and aspects of the disclosure, as well as specific examples thereof, are intended to encompass equivalents thereof. Additionally, the term, “or,” as used herein, refers to a non-exclusive or, unless otherwise indicated.

Unless otherwise specified, use of the terms “connect,” “engage,” “couple,” “attach,” or any other like term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described.

Unless otherwise specified, use of the terms “up,” “upper,” “upward,” “uphole,” “upstream,” or other like terms shall be construed as generally toward the surface of the well; likewise, use of the terms “down,” “lower,” “downward,” “downhole,” or other like terms shall be construed as generally toward the bottom, terminal end of a well, regardless of the wellbore orientation. Use of any one or more of the foregoing terms shall not be construed as denoting positions along a perfectly vertical or horizontal axis. Unless otherwise specified, use of the term “subterranean formation” shall be construed as encompassing both areas below exposed earth and areas below earth covered by water, such as ocean or fresh water.

Referring to FIG. 1, depicted is a perspective view of a well system 100 including an exemplary operating environment that the apparatuses, systems and methods disclosed herein may be employed. For example, the well system 100 could use an expandable metal fishing tool according to any of the embodiments, aspects, applications, variations, designs, etc. disclosed in the following paragraphs. The well system 100 illustrated in FIG. 1 includes a rig 110 extending over and around a wellbore 120 formed in a subterranean formation 130. As those skilled in the art appreciate, the wellbore 120 may be fully cased, partially cased, or an open hole wellbore. In the illustrated embodiment of FIG. 1, the wellbore 120 is partially cased, and thus includes a cased region 140 and an open hole region 145. The cased region 140, as is depicted, may employ casing 150 that is held into place by cement 160.

The well system 100 illustrated in FIG. 1 additionally includes one or more production tubing 170 located within the wellbore 120. In the illustrated embodiment of FIG. 1, the well system 100 includes a first production tubing 175A, as well as a second production tubing 175B, as might be used in a multi-completion well system. Other embodiments exist, however, where more or less than two production tubing 170 are located within the wellbore 120. The production tubing 170, in the illustrated embodiment, has been cut, for example if there was a need to replace a portion of the production tubing 170, plug and abandon a portion of the production tubing 170, or for any other known or hereafter discovered reason.

Coupled to the production tubing 170 in the embodiment of FIG. 1, are one or more expandable metal fishing tools 180. In accordance with the embodiment of FIG. 1, a first expandable metal fishing tool 185A is coupled to the first production tubing 175A, and a second expandable metal fishing tool 185B is coupled to the second production tubing 175B. The first expandable metal fishing tool 185A, in the illustrated embodiment, is coupled to a downhole end of a downhole conveyance 190 (e.g., replacement production tubing in one embodiment). Accordingly, the first expandable metal fishing tool 185A, when set, may provide sealed fluid communication between the downhole conveyance 190 and the first production tubing 175A, as might be necessary when repairing or replacing a portion of the production tubing. The second expandable metal fishing tool 185B, in the illustrated embodiment, is coupled to an uphole end of the second production tubing 175B. Accordingly, the second expandable metal fishing tool 185B, seals all fluid communication from the second production tubing 175B, and thus may be used to plug and abandon the second production tubing 175B, among other uses.

In accordance with one embodiment of the disclosure, each of the first and second expandable metal fishing tools 185A, 185B, include a mandrel having an interior surface and an exterior surface. Each of the first and second expandable metal fishing tools 185A, 185B according to this embodiment, may further include one or more expandable members positioned at least partially along the interior surface, wherein the one or more expandable members comprise a metal configured to expand in response to hydrolysis, and further wherein a combined volume of the one or more expandable members is sufficient to expand radially inwardly to engage the first or second production tubing 175A, 175B within the wellbore 120 in response to the hydrolysis.

In some embodiments, all or part of the one or more expandable members may be fabricated using an expanding metal configured to expand in response to hydrolysis. The expanding metal, in some embodiments, may be described as expanding to a cement like material. In other words, the metal goes from metal to micron-scale particles and then these particles expand and lock together to, in essence, lock the expandable metal fishing tools 180 in place. The reaction may, in certain embodiments, occur in less than 2 days in a reactive fluid and in downhole temperatures. Nevertheless, the time of reaction may vary depending on the reactive fluid, the expandable metal used, and the downhole temperature.

In some embodiments the reactive fluid may be a brine solution such as may be produced during well completion activities, and in other embodiments, the reactive fluid may be one of the additional solutions discussed herein. The metal, pre-expansion, is electrically conductive in certain embodiments. The metal may be machined to any specific size/shape, extruded, formed, cast or other conventional ways to get the desired shape of a metal, as will be discussed in greater detail below. Metal, pre-expansion, in certain embodiments has a yield strength greater than about 8,000 psi, e.g., 8,000 psi+/−50%. The metal, in one embodiment, has a minimum dimension greater than about 1.25 mm (e.g., approximately 0.05 inches).

The hydrolysis of any metal can create a metal hydroxide. The formative properties of alkaline earth metals (Mg—Magnesium, Ca—Calcium, etc.) and transition metals (Zn—Zinc, Al—Aluminum, etc.) under hydrolysis reactions demonstrate structural characteristics that are favorable for use with the present disclosure. Hydration results in an increase in size from the hydration reaction and results in a metal hydroxide that can precipitate from the fluid.

The hydration reactions for magnesium is:

Mg+2H₂O->Mg(OH)₂+H₂,

where Mg(OH)₂ is also known as brucite. Another hydration reaction uses aluminum hydrolysis. The reaction forms a material known as Gibbsite, bayerite, and norstrandite, depending on form. The hydration reaction for aluminum is:

Al+3H₂O->Al(OH)₃+3/2 H₂.

Another hydration reactions uses calcium hydrolysis. The hydration reaction for calcium is:

Ca+2H₂O->Ca(OH)₂+H₂,

Where Ca(OH)₂ is known as portlandite and is a common hydrolysis product of Portland cement. Magnesium hydroxide and calcium hydroxide are considered to be relatively insoluble in water. Aluminum hydroxide can be considered an amphoteric hydroxide, which has solubility in strong acids or in strong bases.

In an embodiment, the metallic material used can be a metal alloy. The metal alloy can be an alloy of the base metal with other elements in order to either adjust the strength of the metal alloy, to adjust the reaction time of the metal alloy, or to adjust the strength of the resulting metal hydroxide byproduct, among other adjustments. The metal alloy can be alloyed with elements that enhance the strength of the metal such as, but not limited to, Al—Aluminum, Zn—Zinc, Mn—Manganese, Zr—Zirconium, Y—Yttrium, Nd—Neodymium, Gd—Gadolinium, Ag—Silver, Ca—Calcium, Sn—Tin, and Re—Rhenium, Cu—Copper. In some embodiments, the alloy can be alloyed with a dopant that promotes corrosion, such as Ni—Nickel, Fe—Iron, Cu—Copper, Co—Cobalt, Ir—Iridium, Au—Gold, C—Carbon, Ga—gallium, Ir—indium, Hg—mercury, Bi—bismuth, Sn—tin, and Pd—Palladium. The metal alloy can be constructed in a solid solution process where the elements are combined with molten metal or metal alloy. Alternatively, the metal alloy could be constructed with a powder metallurgy process. The metal can be cast, forged, extruded, or a combination thereof.

Optionally, non-expanding components may be added to the starting metallic materials. For example, ceramic, elastomer, glass, or non-reacting metal components can be embedded in the expanding metal or coated on the surface of the metal. Alternatively, the starting metal may be the metal oxide. For example, calcium oxide (CaO) with water will produce calcium hydroxide in an energetic reaction. Due to the higher density of calcium oxide, this can have a 260% volumetric expansion where converting 1 mole of CaO goes from 9.5 cc to 34.4 cc of volume. In one variation, the expanding metal is formed in a serpentinite reaction, a hydration and metamorphic reaction. In one variation, the resultant material resembles a mafic material. Additional ions can be added to the reaction, including silicate, sulfate, aluminate, and phosphate. The metal can be alloyed to increase the reactivity or to control the formation of oxides.

The expandable metal can be configured in many different fashions, as long as an adequate volume of material is available for fully expanding. For example, the expandable metal may be formed into a single long tube, granules, multiple short tubes, rings, alternating steel and swellable rubber and expandable metal rings, among others.

Additionally, a coating may be applied to one or more portions of the expandable metal to delay the expanding reactions. For example, the coating may be used to alter the triggering of the chemical reaction of the expanding metal. In one embodiment, the metal is coated with a delay barrier. When the fishing tool encounters the object for retrieval, then the coating is compromised and the reaction can accelerate. In another embodiment, a frangible covering prevents wellbore fluids from reacting with the expanding metal. The frangible covering is broken when the fishing tool encounters the object for retrieval, which allows the wellbore fluids to cause the metal to chemically react. In certain other embodiment, the metal can be heat treated to change the grain size of the metal.

The expandable metal fishing tool 180 can be moved down the wellbore 120 via one or more downhole conveyance 190 to a desired location. Once the expandable metal fishing tool 180 reaches the desired location, and more specifically encircles the production tubing 170, the expandable metal fishing tool 180 may be set in place according to the disclosure. In one embodiment, the expandable metal fishing tool 180 is subjected to a wellbore fluid sufficient to expand the one or more expandable members into contact with the production tubing 170 and thereby couple the expandable metal fishing tool 180 to the production tubing 170.

Turning to FIG. 2, illustrated is a cross-sectional view of one embodiment of an expandable metal fishing tool 200 designed, manufactured and operated according to the disclosure. The expandable metal fishing tool 200, in the illustrated embodiment, includes a mandrel 210. The mandrel 210, in the illustrated embodiment, includes a tubular receiving end 220, a connector end 222, an interior surface 224 and an exterior surface 226. As those skilled in the art may appreciate, the tubular receiving end 220 is that end of the mandrel 210 that is configured to receive a downhole tubular.

Furthermore, the connector end 220 is that end of the mandrel 210 that is configured to couple with a downhole conveyance. In one embodiment, such as that shown in FIG. 2, the connector end 220 is a first threaded connection, which in turn is operable to engage with a second threaded connection on the downhole conveyance, such as replacement production tubing, coiled tubing, etc. While a threaded connection has been illustrated for the connector end 220, those skilled in the art understand the myriad of different types of connectors that might be used and remain within the scope of the disclosure.

The mandrel 210 may comprise many different materials and remain within the scope of the disclosure. For example, the mandrel 210 could comprise a metal, or a metal alloy and remain within the scope of the disclosure. In another embodiment, the mandrel 210 might comprise steel, such as is commonly used in American Petroleum Institute (API) pipe. In yet another embodiment, the mandrel does not comprise a metal configured to expand in response to hydrolysis.

In certain embodiments, such as that shown in FIG. 2, the mandrel 210 provides a fluid path from the tubular receiving end 220 all the way through to the connector end 222. In this embodiment, fluid may traverse entirely through the mandrel 210, such as might be desirable if the expandable metal fishing tool 200 were being used to provide fluid communication from a downhole tubular to the surface of a well system. In other embodiments, the mandrel 210 has a fluid barrier at some point between the tubular receiving end 220 and the connector end 222. In many embodiments, the fluid barrier is located more proximate the connector end 222 than the tubular receiving end 220, such that the expandable metal fishing tool could still engage with the downhole tubular. In this embodiment, fluid may not traverse entirely through the mandrel 210, such as might be desirable if the expandable metal fishing tool 200 were being used in a plug and abandonment type of application.

The interior surface 224 of the mandrel 210 helps create an interior diameter (D_(M)) thereof. In accordance with one embodiment, the interior diameter (D_(M)) of the mandrel 210 is large enough to encircle a downhole tubular, even though one or more expandable members are positioned at least partially along the interior surface 224 thereof. Accordingly, the interior diameter (D_(M)) of the mandrel 210 may be chosen based upon the thickness (T) of the one or more expandable members, as well as the diameter of the downhole tubular. Nevertheless, in one embodiment, the interior diameter (D_(M)) is at least about 3.5 cm. In another embodiment, the interior diameter (D_(M)) is at least 12 cm, and in yet another embodiment the interior diameter (D_(M)) ranges from about 2 cm to about 25 cm. While certain values for the interior diameter (D_(M)) have been given, the present disclosure should not be so limited. Notwithstanding the foregoing values, other embodiments exist wherein the lower range is ½ of that listed, and the upper range is 2× that listed.

The expandable metal fishing tool 200 illustrated in FIG. 2 additionally includes one or more expandable members 230 positioned at least partially along the interior surface 224. As detailed above, the one or more expandable members 230 may comprise a metal configured to expand in response to hydrolysis. As further discussed above, a combined volume of the one or more expandable members 230 should be sufficient to expand radially inwardly to engage the downhole tubular in response to the hydrolysis. In one embodiment, the combined volume of the one or more expandable members 220 is sufficient to expand to anchor at least about 100,000 Newtons (e.g., about 25,000 lbs.) of weight within the wellbore. In yet another embodiment, the combined volume of the one or more expandable members 220 is sufficient to expand to anchor at least about 200,000 Newtons (e.g., about 50,000 lbs.) of weight within the wellbore, and in yet another embodiment sufficient to expand to anchor at least about 450,000 Newtons (e.g., about 100,000 lbs.) of weight within the wellbore.

The volume of the one or more expandable members 230, in the illustrated embodiment, may be determined by the shape of the one or more expandable members 230, the length (L) of the one or more expandable members 230, and the thickness (T) of the one or more expandable members 230. In accordance with one embodiment, the length (L) (e.g., pre-expansion) is at least about 5.3 cm, if not at least about 10 cm. In another embodiment, length (L) is at least about 22.9 cm, if not at least about 50 cm. In yet another embodiment the length (L) ranges from about 2 cm to about 300 cm. Similarly, in one embodiment the thickness (T) (e.g., pre-expansion) is at least about 0.1 cm, if not at least about 0.3 cm. In another embodiment, the thickness (T) is at least 1 cm, and in yet another embodiment the thickness (T) ranges from about 0.05 cm to about 3 cm. While certain values for the length (L) and thickness (T) have been given for the one or more expandable members 230, the present disclosure should not be so limited.

In accordance with one embodiment, the interior diameter (D_(E)) (e.g., pre-expansion) of the one or more expandable members 230 is large enough to encircle a downhole tubular. Accordingly, the interior diameter (D_(E)) of the one or more expandable members 230 may be chosen based upon the thickness (T) of the one or more expandable members 230, as well as the diameter of the downhole tubular. Nevertheless, in one embodiment, the interior diameter (D_(E)) is at least about 2.9 cm, if not at least about 4.5 cm. In another embodiment, the interior diameter (D_(E)) is at least 11 cm, and in yet another embodiment the interior diameter (D_(E)) ranges from about 1 cm to about 24 cm. While certain values for the interior diameter (D_(E)) have been given, the present disclosure should not be so limited.

The one or more expandable members 230, in the illustrated embodiment of FIG. 2, include one or more alignment ramps 240 for directing the downhole tubular inside of the mandrel 210. The alignment ramps 240 may take on many different configurations and remain within the scope of the disclosure. In the embodiment of FIG. 2, the alignment ramps 240 are inwardly sloping features operable to engage the downhole tubular and direct it to a center point of the one or more expandable member 230. The angle of the inwardly sloping features may vary, but in one embodiment is greater than 45 degrees, and in yet another embodiment is greater than 60 degrees (e.g., from horizontal in the depiction of FIG. 2).

Turning to FIG. 3, illustrated is a cross-sectional view of another embodiment of an expandable metal fishing tool 300 designed, manufactured and operated according to the disclosure. The expandable metal fishing tool 300 is similar in many respects to the expandable metal fishing tool 200 illustrated and described with respect to FIG. 2. Accordingly, like reference numbers have been used to indicate similar, if not identical, features. The expandable metal fishing tool 300 differs, for the most part, from the expandable metal fishing tool 200, in that the expandable metal fishing tool 300 includes a seal 310 positioned proximate the one or more expandable members 230. In the embodiment of FIG. 3, the seal 310 is configured to seal radially inward against the downhole tubular, as might be desirable if one were looking for a pressure spike to confirm that the expandable metal fishing tool 300 has appropriately engaged the downhole tubular. In one embodiment, the seal 310 is a cup seal.

In accordance with one embodiment, the interior diameter (Ds) of the seal 310 is large enough to encircle a downhole tubular, but small enough to create a seal when the seal 310 encircles the downhole tubular. Accordingly, the interior diameter (Ds) of the seal 310 may be chosen based upon the diameter of the downhole tubular, and more particularly chosen to be similar to or slightly less than the diameter of the downhole tubular. Accordingly, in one embodiment, the interior diameter (Ds) is at least about 2.6 cm, if not at least about 4 cm. In another embodiment, the interior diameter (Ds) is at least 8 cm, if not at least about 11.2 cm, and in yet another embodiment the interior diameter (Ds) ranges from about 1 cm to about 24 cm. While certain values for the interior diameter (Ds) have been given, the present disclosure should not be so limited.

The seal 310 may comprise many different materials, configurations and locations and remain within the scope of the disclosure. While the seal 310 is located proximate a midpoint of the one or more expandable members 230 in the embodiment of FIG. 3, other embodiments may exist wherein the seal 310 is located proximate the tubular receiving end 220 of the mandrel 210. Moreover, in yet other embodiments, the seal 310 may be located more proximate the connector end 222 of the mandrel 210 than the tubular receiving end 220 of the mandrel 210.

In one embodiment, the seal 310 is a compressible rubber seal member. In another embodiment, the seal 310 is a swellable rubber seal member. In another embedment, the seal 310 is a cup seal member. In accordance with this embodiment, the swellable rubber seal member may be configured to swell in response to contact with one or more downhole fluids. The swellable rubber seal member, when used, may be configured to swell in response to contact with one or more downhole reactive fluids to pressure seal against the downhole tubular, as well as pressure seal against the mandrel 210. In one embodiment, the reactive fluid may be a diesel solution, or other similar water-based solution, among others.

Turning now to FIGS. 4-9, illustrated are perspective views of various different expandable members, as might be used with an expandable metal fishing tool according to the disclosure. Specifically, the various different expandable members illustrated in FIGS. 4-9 could be positioned along the interior surface of the mandrel of an expandable metal fishing tool, according to the disclosure. While certain specific embodiments have been given for expandable members according to the disclosure, the present disclosure should not be limited to only those designs illustrated in FIGS. 4-9.

Turning initially to FIG. 4, illustrated is an expandable member 400 designed, manufactured and operated according to the disclosure. The expandable member 400, in the illustrated embodiment, comprises a single expandable sleeve 410, as might be positioned along the interior surface of the mandrel. In the illustrated embodiment, the single expandable sleeve 410 includes one or more openings extending entirely through a wall thickness thereof for accepting a fastener 420 (e.g., a set screw in one embodiment). The fastener 420, in this embodiment, may be used to fix the single expandable sleeve 410 to the interior surface of the mandrel of the expandable metal fishing tool. As those skilled in the art now appreciate, the single expandable sleeve 410 will expand radially inward to engage a downhole tubular within a wellbore in response to the hydrolysis. While not illustrated, an opposing end of the single expandable sleeve 410 may be closed, whether using additional expandable metal, or another feature. Accordingly, the single expandable sleeve 410 could be used in a plug and abandonment situation.

Turning briefly to FIG. 5, illustrated is an alternative embodiment of an expandable member 500. The expandable member 500 is similar in certain respects to the expandable member 400. Accordingly, like reference numerals have been used to reference similar, if not identical, features. The expandable member 500 differs, for the most part, from the expandable member 400, in that the expandable member 500 includes a pair of retaining rings 510, for example positioned adjacent a proximal end and a distal end of the single expandable sleeve 410. In accordance with one embodiment of the disclosure, the pair of retaining rings 510 does not comprise the metal configured to expand in response to hydrolysis, and moreover includes the one or more fasteners 420, to fix the single expandable sleeve 410 to the interior surface of the mandrel of the expandable metal fishing tool.

Turning briefly to FIG. 6, illustrated is an alternative embodiment of an expandable member 600. The expandable member 600 is similar in certain respects to the expandable member 400. Accordingly, like reference numerals have been used to reference similar, if not identical, features. The expandable member 600 differs, for the most part, from the expandable member 400, in that the expandable member 600 includes two separate expandable halves 610, 620, for extending along a length of the mandrel. While the expandable halves 610, 620 are illustrated as complementary halves being positioned directly next to one another, or even in contact, other embodiments may exist wherein a space exists between the expandable halves 610, 620. Such a space will fill when the expandable halves 610, 620 expand in response to the hydrolysis.

Turning briefly to FIG. 7, illustrated is an alternative embodiment of an expandable member 700. The expandable member 700 is similar in certain respects to the expandable member 400. Accordingly, like reference numerals have been used to reference similar, if not identical, features. The expandable member 700 differs, for the most part, from the expandable member 400, in that the expandable member 600 includes three or more expandable members (e.g., four expandable members 710, 720, 730, 740), for extending along a length of the mandrel. In accordance with this embodiment, the three or more expandable members (e.g., four expandable members 710, 720, 730, 740) are substantially equally radially spaced from each other, and thus when positioned within the mandrel, are substantially equally radially spaced about the interior surface of the mandrel. As discussed above, any space existing between the three or more expandable members (e.g., four expandable members 710, 720, 730, 740) will fill when the three or more expandable members (e.g., four expandable members 710, 720, 730, 740) expand in response to hydrolysis.

Turning briefly to FIG. 8, illustrated is an alternative embodiment of an expandable member 800. The expandable member 800 is similar in certain respects to the expandable member 500. Accordingly, like reference numerals have been used to reference similar, if not identical, features. The expandable member 800 differs, for the most part, from the expandable member 500, in that the expandable member 800 includes two or more separate expandable sleeves (e.g., six expandable sleeves 810, 820, 830, 840, 850) for extending along a length of the mandrel. The number of separate expandable sleeves may be chosen based upon the amount of engagement, anchoring and/or sealing that is desired for the expandable metal fishing tool.

Turning briefly to FIG. 9, illustrated is an alternative embodiment of an expandable member 900. The expandable member 900 is similar in certain respects to the expandable member 400. Accordingly, like reference numerals have been used to reference similar, if not identical, features. The expandable member 900 differs, for the most part, from the expandable member 400, in that the expandable member 900 includes a seal 910, the seal 910 configured to seal radially inward against the downhole tubular. In the illustrated embodiment of FIG. 9, the seal 910 is a swellable rubber seal member configured to swell in response to contact with one or more downhole fluids, for example to seal radially inward against the tubular and radially outward against the mandrel.

Turning to FIG. 10, illustrated is a cross-sectional view of another embodiment of an expandable metal fishing tool 1000 designed, manufactured and operated according to the disclosure. The expandable metal fishing tool 1000 is similar in certain respects to the expandable metal fishing tool 200. Accordingly, like reference numerals have been used to reference similar, if not identical, features. The expandable metal fishing tool 1000 differs, for the most part, from the expandable metal fishing tool 200, in that the expandable metal fishing tool 1000 is configured to extend within an opening in a downhole tubular, as opposed to be positioned around an exterior of the downhole tubular, as is the case with the expandable metal fishing tool 200. Accordingly, the one or more expandable members 1030 are positioned on the exterior surface 226, and furthermore are configured to radially outwardly expand to engage the opening in the downhole tubular. It should be noted that the one or more expandable member 1030 may embody many of the same shapes as the one or more expandable members illustrated in FIGS. 4-9 above.

Turning now to FIGS. 11A-11C, illustrated are different cross-sectional views of a well system 1100 including an expandable metal fishing tool 1110, 1160 at various different stages of use. Accordingly, FIGS. 11A-11C are used to illustrate one method for setting the expandable metal fishing tool 1110 in accordance with the disclosure. The expandable metal fishing tool 1110 is similar in certain respects to the expandable metal fishing tool 300 described above with regard to FIG. 3. Accordingly, like reference numerals have been used to reference similar, if not identical, features.

With initial reference to FIG. 11A, the expandable metal fishing tool 1110 is coupled to a downhole end of a downhole conveyance 1120. In this embodiment, the downhole conveyance 1120 and the expandable metal fishing tool 1110 have been positioned within a wellbore 1130 of a subterranean formation 1140. The downhole conveyance 1120, in the illustrated embodiment, is replacement production tubing, but in other embodiments might be drill pipe, coiled tubing, or the like. The expandable metal fishing tool 1110, in the illustrated embodiment, is positioned above, but not encircling (e.g., around), a downhole tubular 1150. Furthermore, the expandable metal fishing tool 1110 is in its pre-expansion state.

Turning now to FIG. 11B, illustrated is the well system 1100 of FIG. 11A, after positioning the tubular receiving end 220 of the mandrel 210 and the one or more expandable members 230 of the pre-expansion expandable metal fishing tool 1110 around (e.g., encircling) the downhole tubular 1150. As discussed above, the one or more alignment ramps 240 may help direct the downhole tubular 1150 inside of the mandrel 210. Furthermore, the seal 310 may engage with the downhole tubular 1150 to provide a fluid seal there between. Accordingly, the existence of a pressure spike may confirm that the expandable metal fishing tool 1110 has appropriately engaged the downhole tubular 1150.

Turning now to FIG. 11C, illustrated is the well system 1100 of FIG. 11B, after subjecting the pre-expansion expandable metal fishing tool 1110 positioned around the downhole tubular 1150 to a wellbore fluid for a requisite period of time. Accordingly, the one or more expandable members 230 radially expand inward to engage the downhole tubular 1150 in response to the hydrolysis. What results, is a post expansion expandable metal fishing tool 1160.

In the embodiment of FIGS. 11A-11C, the metal is a magnesium alloy or a magnesium alloy alloyed with at least one of Al, Zn, Mn, Zr, Y, Nd, Gd, Ag, Ca, Sn, and Re. Furthermore, in the embodiment of FIGS. 11A-11C, the metal is configured to expand in response to one of magnesium hydrolysis, aluminum hydrolysis, calcium hydrolysis, and calcium oxide hydrolysis. Additionally, in the embodiment of FIGS. 11-11C, the hydrolysis forms a structure comprising one of a Brucite, Gibbsite, bayerite, and norstrandite, among others.

While the embodiment discussed above with regard to FIGS. 11A-11C is directed to a fishing tool 1110 that extends around a downhole tubular 1150, such as is the case if the fishing tool 1110 was operating as an overshot tool, similar principles could also be used for a situation wherein the fishing tool is configured to extend within an opening in the downhole tubular 1150. Accordingly, the present disclosure, not the method discussed above with regard to FIGS. 11A-11C, should not be limited to just those situations wherein the fishing tool is operating as an overshot tool.

Aspects disclosed herein include:

A. An expandable metal fishing tool for use in a wellbore, the expandable metal fishing tool including: 1) a mandrel; 2) one or more expandable members positioned at least partially along an interior surface or an exterior surface of the mandrel, wherein the one or more expandable members comprise a metal configured to expand in response to hydrolysis, and

wherein a combined volume of the one or more expandable members is sufficient to expand radially to engage a downhole tubular within a wellbore in response to the hydrolysis.

B. A well system, the well system including: 1) a wellbore positioned within a subterranean formation; 2) a downhole conveyance located within the wellbore, the downhole conveyance having an expandable metal fishing tool coupled to a downhole end thereof, the expandable metal fishing tool including a) a mandrel; b) one or more expandable members positioned at least partially along an interior surface or an exterior surface of the mandrel, and wherein the one or more expandable members comprise a metal configured to expand in response to hydrolysis; and 3) a downhole tubular located within the wellbore, the one or more expandable members having expanded radially to engage the downhole tubular in response to the hydrolysis.

C. A method for setting an expandable metal fishing tool, the method including: 1) positioning a downhole conveyance within a wellbore of a subterranean formation, the downhole conveyance having an pre-expansion expandable metal fishing tool coupled to a downhole end thereof, the expandable metal fishing tool including; a) a mandrel having a receiving end and a connector end; b) one or more expandable members positioned at least partially along an interior surface or an exterior surface of the mandrel, and wherein the one or more expandable members comprise a metal configured to expand in response to hydrolysis; 2) positioning the receiving end of the mandrel and the one or more expandable members of the pre-expansion expandable metal fishing tool around a downhole tubular or within an opening of the downhole tubular; and 3) subjecting the pre-expansion expandable metal fishing tool positioned around the downhole tubular or within the opening of the downhole tubular to a wellbore fluid, the one or more expandable members radially expanding to engage the downhole tubular in response to the hydrolysis.

Aspects A, B, and C may have one or more of the following additional elements in combination: Element 1: wherein the mandrel is a tubular mandrel having the interior surface, and further wherein the one or more expandable members are positioned at least partially along the interior surface, such that the combined volume of the one or more expandable members is sufficient to expand radially inwardly to engage the downhole tubular. Element 2: wherein the one or more expandable members is a single expandable sleeve lining at least a portion of the interior surface. Element 3: wherein the single expandable sleeve further includes one or more openings extending entirely through a wall thickness thereof for accepting one or more fasteners for fixing the single expandable sleeve to the interior surface. Element 4: wherein the one or more expandable members are two or more separate expandable sleeves positioned at least partially along the interior surface. Element 5: further including a pair of retaining rings positioned adjacent at opposing ends of the two or more separate sleeves for fixing the two or more separate expandable sleeves along the interior surface. Element 6: wherein the pair of retaining rings does not comprise the metal configured to expand in response to hydrolysis. Element 7: wherein the one or more expandable members positioned at least partially along the interior surface are two expandable members axially positioned along the interior surface. Element 8: wherein the one or more expandable members positioned at least partially along the interior surface are three or more expandable members axially positioned along and substantially equally radially spaced about the interior surface. Element 9: further including a seal positioned proximate the one or more expandable members, wherein the seal is configured to seal radially inward against the downhole tubular. Element 10: wherein the seal is a swellable rubber seal member positionable proximate the one or more expandable members, wherein the swellable rubber seal member is configured to swell in response to contact with one or more downhole fluids to seal radially inward against the downhole tubular and radially outward against the mandrel. Element 11: wherein the mandrel has a tubular receiving end for receiving the downhole tubular and a connector end for connecting to a downhole conveyance. Element 12: wherein the connector end is a first threaded connection for engaging with a second threaded connection on replacement production tubing. Element 13: wherein the one or more expandable members include one or more alignment ramps for directing the downhole tubular inside of the mandrel. Element 14: wherein the one or more expandable members have a length (L) of at least about 5.3 cm. Element 15: wherein the one or more expandable members are positioned at least partially along the exterior surface, such that the combined volume of the one or more expandable members is sufficient to expand radially outwardly to engage an opening in the downhole tubular. Element 16: wherein the downhole conveyance is replacement production tubing and the downhole tubular is cut production tubing. Element 17: wherein the expandable metal fishing tool is an expandable metal plug and the downhole tubular is cut production tubing. Element 18: wherein the mandrel is a tubular mandrel having the interior surface, and further wherein the one or more expandable members are positioned at least partially along the interior surface, such that the combined volume of the one or more expandable members is sufficient to expand radially inwardly to engage the downhole tubular. Element 19: wherein the one or more expandable members are positioned at least partially along the exterior surface, such that the combined volume of the one or more expandable members is sufficient to expand radially outwardly to engage an opening in the downhole tubular. Element 20: wherein the metal is configured to expand in response to one of magnesium hydrolysis, aluminum hydrolysis, calcium hydrolysis, and calcium oxide hydrolysis. Element 21: wherein the hydrolysis forms a structure comprising one of a Brucite, Gibbsite, bayerite, and norstrandite. Element 22: wherein the metal is a magnesium alloy or a magnesium alloy alloyed with at least one of Al, Zn, Mn, Zr, Y, Nd, Gd, Ag, Ca, Sn, and Re. Element 23: wherein the mandrel is a tubular mandrel having the interior surface, and further wherein the one or more expandable members are positioned at least partially along the interior surface, and further wherein positioning the receiving end includes positioning the receiving end around the downhole tubular, and wherein subjecting the pre-expandable metal fishing tool includes subjecting the pre-expansion expandable metal fishing tool positioned around the downhole tubular to the wellbore fluid, the one or more expandable members radially inwardly expanding to engage the downhole tubular in response to the hydrolysis. Element 24: wherein the one or more expandable members are positioned at least partially along the exterior surface, and further wherein positioning the receiving end includes positioning the receiving end within the opening in the downhole tubular, and wherein subjecting the pre-expandable metal fishing tool includes subjecting the pre-expansion expandable metal fishing tool positioned within the opening of the downhole tubular to the wellbore fluid, the one or more expandable members radially outwardly expanding to engage the downhole tubular in response to the hydrolysis.

Those skilled in the art to which this application relates will appreciate that other and further additions, deletions, substitutions and modifications may be made to the described embodiments. 

What is claimed is:
 1. An expandable metal fishing tool for use in a wellbore, comprising: a mandrel; one or more expandable members positioned at least partially along an interior surface or an exterior surface of the mandrel; wherein the one or more expandable members comprise a metal configured to expand in response to hydrolysis; and wherein a combined volume of the one or more expandable members is sufficient to expand radially to engage a downhole tubular within a wellbore in response to the hydrolysis.
 2. The expandable metal fishing tool as recited in claim 1, wherein the mandrel is a tubular mandrel having the interior surface, and further wherein the one or more expandable members are positioned at least partially along the interior surface, such that the combined volume of the one or more expandable members is sufficient to expand radially inwardly to engage the downhole tubular.
 3. The expandable metal fishing tool as recited in claim 2, wherein the one or more expandable members is a single expandable sleeve lining at least a portion of the interior surface.
 4. The expandable metal fishing tool as recited in claim 3, wherein the single expandable sleeve further includes one or more openings extending entirely through a wall thickness thereof for accepting one or more fasteners for fixing the single expandable sleeve to the interior surface.
 5. The expandable metal fishing tool as recited in claim 2, wherein the one or more expandable members are two or more separate expandable sleeves positioned at least partially along the interior surface.
 6. The expandable metal fishing tool as recited in claim 5, further including a pair of retaining rings positioned adjacent at opposing ends of the two or more separate sleeves for fixing the two or more separate expandable sleeves along the interior surface.
 7. The expandable metal fishing tool as recited in claim 6, wherein the pair of retaining rings does not comprise the metal configured to expand in response to hydrolysis.
 8. The expandable metal fishing tool as recited in claim 2, wherein the one or more expandable members positioned at least partially along the interior surface are two expandable members axially positioned along the interior surface.
 9. The expandable metal fishing tool as recited in claim 2, wherein the one or more expandable members positioned at least partially along the interior surface are three or more expandable members axially positioned along and substantially equally radially spaced about the interior surface.
 10. The expandable metal fishing tool as recited in claim 2, further including a seal positioned proximate the one or more expandable members, wherein the seal is configured to seal radially inward against the downhole tubular.
 11. The expandable metal fishing tool as recited in claim 10, wherein the seal is a swellable rubber seal member positionable proximate the one or more expandable members, wherein the swellable rubber seal member is configured to swell in response to contact with one or more downhole fluids to seal radially inward against the downhole tubular and radially outward against the mandrel.
 12. The expandable metal fishing tool as recited in claim 2, wherein the mandrel has a tubular receiving end for receiving the downhole tubular and a connector end for connecting to a downhole conveyance.
 13. The expandable metal fishing tool as recited in claim 12, wherein the connector end is a first threaded connection for engaging with a second threaded connection on replacement production tubing.
 14. The expandable metal fishing tool as recited in claim 12, wherein the one or more expandable members include one or more alignment ramps for directing the downhole tubular inside of the mandrel.
 15. The expandable metal fishing tool as recited in claim 1, wherein the one or more expandable members have a length (L) of at least about 5.3 cm.
 16. The expandable metal fishing tool as recited in claim 1, wherein the one or more expandable members are positioned at least partially along the exterior surface, such that the combined volume of the one or more expandable members is sufficient to expand radially outwardly to engage an opening in the downhole tubular.
 17. A well system, comprising: a wellbore positioned within a subterranean formation; a downhole conveyance located within the wellbore, the downhole conveyance having an expandable metal fishing tool coupled to a downhole end thereof, the expandable metal fishing tool including; a mandrel; one or more expandable members positioned at least partially along an interior surface or an exterior surface of the mandrel; and wherein the one or more expandable members comprise a metal configured to expand in response to hydrolysis; and a downhole tubular located within the wellbore, the one or more expandable members having expanded radially to engage the downhole tubular in response to the hydrolysis.
 18. The well system as recited in claim 17, wherein the downhole conveyance is replacement production tubing and the downhole tubular is cut production tubing.
 19. The well system as recited in claim 17, wherein the expandable metal fishing tool is an expandable metal plug and the downhole tubular is cut production tubing.
 20. The well system as recited in claim 17, wherein the mandrel is a tubular mandrel having the interior surface, and further wherein the one or more expandable members are positioned at least partially along the interior surface, such that the combined volume of the one or more expandable members is sufficient to expand radially inwardly to engage the downhole tubular.
 21. The well system as recited in claim 17, wherein the one or more expandable members are positioned at least partially along the exterior surface, such that the combined volume of the one or more expandable members is sufficient to expand radially outwardly to engage an opening in the downhole tubular.
 22. A method for setting an expandable metal fishing tool, comprising: positioning a downhole conveyance within a wellbore of a subterranean formation, the downhole conveyance having an pre-expansion expandable metal fishing tool coupled to a downhole end thereof, the expandable metal fishing tool including; a mandrel having a receiving end and a connector end; one or more expandable members positioned at least partially along an interior surface or an exterior surface of the mandrel; and wherein the one or more expandable members comprise a metal configured to expand in response to hydrolysis; positioning the receiving end of the mandrel and the one or more expandable members of the pre-expansion expandable metal fishing tool around a downhole tubular or within an opening of the downhole tubular; and subjecting the pre-expansion expandable metal fishing tool positioned around the downhole tubular or within the opening of the downhole tubular to a wellbore fluid, the one or more expandable members radially expanding to engage the downhole tubular in response to the hydrolysis.
 23. The method as recited in claim 22, wherein the metal is configured to expand in response to one of magnesium hydrolysis, aluminum hydrolysis, calcium hydrolysis, and calcium oxide hydrolysis.
 24. The method as recited in claim 22, wherein the hydrolysis forms a structure comprising one of a Brucite, Gibbsite, bayerite, and norstrandite.
 25. The method as recited in claim 22, wherein the metal is a magnesium alloy or a magnesium alloy alloyed with at least one of Al, Zn, Mn, Zr, Y, Nd, Gd, Ag, Ca, Sn, and Re.
 26. The method as recited in claim 22, wherein the mandrel is a tubular mandrel having the interior surface, and further wherein the one or more expandable members are positioned at least partially along the interior surface, and further wherein positioning the receiving end includes positioning the receiving end around the downhole tubular, and wherein subjecting the pre-expandable metal fishing tool includes subjecting the pre-expansion expandable metal fishing tool positioned around the downhole tubular to the wellbore fluid, the one or more expandable members radially inwardly expanding to engage the downhole tubular in response to the hydrolysis.
 27. The method as recited in claim 22, wherein the one or more expandable members are positioned at least partially along the exterior surface, and further wherein positioning the receiving end includes positioning the receiving end within the opening in the downhole tubular, and wherein subjecting the pre-expandable metal fishing tool includes subjecting the pre-expansion expandable metal fishing tool positioned within the opening of the downhole tubular to the wellbore fluid, the one or more expandable members radially outwardly expanding to engage the downhole tubular in response to the hydrolysis. 